Severe Hyponatremia Correction, Mortality, and Central Pontine Myelinolysis

BACKGROUND: In clinical practice, sodium correction rates are frequently limited in patients with severe hyponatremia to prevent neurologic complications. The implications of correction rates on overall mortality and length of hospital stay are unclear. METHODS: In this multicenter observational study, we evaluated the association of sodium correction rates with mortality, length of stay, and central pontine myelinolysis (CPM) in patients hospitalized with severe hyponatremia (admission serum sodium level less than 120 mEq/l). RESULTS: The cohort included 3274 patients. A correction rate of less than 6 mEq/l/24 hours was observed in 38%, 6 to 10 mEq/l/24 hours was observed in 29%, and greater than 10 mEq/l/24 hours was observed in 33%. Compared with 6 to 10 mEq/l/24 hours, a correction rate of less than 6 mEq/l/24 hours exhibited higher in-hospital mortality in multivariable-adjusted and propensity score–weighted analyses. Compared with 6 to 10 mEq/l/24 hours, a correction rate of greater than 10 mEq/l/24 hours was associated with lower in-hospital mortality and shorter length of stay in multivariable analyses. Seven patients with CPM were identified, with five of seven developing CPM despite a sodium correction rate of less than or equal to 8 mEq/l/24 hours. Six of seven patients who developed CPM had alcohol use disorder, malnutrition, hypokalemia, or hypophosphatemia. CONCLUSIONS: Limiting the sodium correction rate was associated with higher mortality and longer length of stay. Whether the sodium correction rate influences neurologic complications needs further evaluation.